Dose-related effects of prolonged NaHCO3 ingestion during high-intensity exercise

Purpose: Sodium bicarbonate (NaHCO3) ingestion may prevent exercise-induced perturbations in acid-base balance, thus resulting in performance enhancement. This study aimed to determine whether different levels of NaHCO3 intake influences acid-base balance and performance during high-intensity exercise after 5 d of supplementation. Methods: Twenty-four men (22 ± 1.7 yr) were randomly assigned to one of three groups (eight subjects per group): control (C, placebo), moderate NaHCO3 intake (MI, 0.3 g·kg-1·d-1), and high NaHCO3 intake (HI, 0.5 g·kg-1·d-1). Arterial pH, HCO3-, PO2, PCO2, K+, Na+, base excess (BE), lactate, and mean power (MP) were measured before and after a Wingate test pre- and postsupplementation. Results: HCO3- increased proportionately to the dosage level. No differences were detected in C. Supplementation increased MP (W·kg-1) in MI (7.36 ± 0.7 vs 6.73 ± 1.0) and HI (7.72 ± 0.9 vs 6.69 ± 0.6), with HI being more effective than MI. NaHCO3 ingestion resulted postexercise in increased lactate (mmol·L-1) (12.3 ± 1.8 vs 10.3 ± 1.9 and 12.4 ± 1.2 vs 10.4 ± 1.5 in MI and HI, respectively), reduced exercise-induced drop of pH (7.305 ± 0.04 vs 7.198 ± 0.02 and 7.343 ± 0.05 vs 7.2 ± 0.01 in MI and HI, respectively) and HCO3- (mmol·L-1) (13.1 ± 2.4 vs 17.5 ± 2.8 and 13.2 ± 2.7 vs 19.8 ± 3.2 for HCO3 in MI and HI, respectively), and reduced K+ (3.875 ± 0.2 vs 3.625 ± 0.3 mmol·L-1 in MI and HI, respectively). Conclusion: NaHCO3 administration for 5 d may prevent acid-base balance disturbances and improve performance during anaerobic exercise in a dose-dependent manner.